1. Technical Field
The present invention relates to a liquid crystal display that drives liquid crystal by means of a transverse electric field, and an electronic apparatus having the same. In particular, the present invention relates to a transflective liquid crystal display that includes a plurality of pixels, each having a transmissive region and a reflective region, and a retardation film being formed in the reflective region.
2. Related Art
Recently, for the purpose of realizing a wide viewing angle of a liquid crystal display used in a cellular phone or a mobile computer, liquid crystal displays, such as an FFS (Fringe Field Switching) mode liquid crystal display and an IPS (In Plane Switching) mode liquid crystal display, which drive liquid crystal by means of a transverse electric field, have been put to practical use. Such liquid crystal displays include a transflective liquid crystal display, which a plurality of pixels each having a transmissive region and a reflective region.
Supposing the effect of a viewing angle dependency of a retardation plate is minimized, in order to eliminate a difference in retardation when the length of a path followed by light varies in a transmissive mode and a reflective mode, the following configuration is suggested (see JP-A-2005-338256):    (a) a retardation film is provided in the reflective region,    (b) a first polarizing plate and a second polarizing plate are disposed such that their polarization axes are perpendicular to each other,    (c) an alignment direction of liquid crystal is in parallel with the polarization axis of the first polarizing plate,    (d) an angle between a slow axis of the retardation film and the polarization axis of the first polarizing plate is approximately 22.5°,    (e) the retardation of a liquid crystal layer in the reflective region is quarter wavelength, and    (f) the retardation of the retardation film is half wavelength.
That is, on the condition that display in the transmissive mode is not obstructed, the retardation film is only formed in the reflective region. Simultaneously, the polarization axis of the polarizing plate and the alignment direction of liquid crystal are set to be in parallel with each other or perpendicular to each other. In addition, the phase difference of the liquid crystal layer in the reflective region is set to be quarter wavelength, and the phase difference in the retardation film is set to be half wavelength.
However, a portable electronic apparatus, such as a cellular phone or a mobile computer, is used outdoor, as well as indoor, and a usage environmental temperature is changed. Nevertheless, in the liquid crystal display described in JP-A-2005-338256, a display characteristic when the usage environment temperature is changed is not taken into consideration. For this reason, when the liquid crystal display disclosed in JP-A-2005-338256 is used at a temperature other than a room temperature, there is a problem in that the contrast of an image displayed in the reflective mode is degraded.